Area Forecast Discussion
Issued by NWS Honolulu, HI

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FXHW60 PHFO 301934
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
930 AM HST TUE SEP 30 2014

.SYNOPSIS...
LIGHT WINDS ACROSS THE STATE COMBINED WITH AN UNSTABLE AIRMASS WILL
RESULT IN A CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH THIS EVENING.
A MORE STABLE AIRMASS IS EXPECTED FOR THE SECOND HALF OF THE
WEEK...BUT LIGHT WINDS AND MUGGY CONDITIONS WILL REMAIN.

&&

.DISCUSSION...
HAVE UPDATED FORECAST TO REMOVE HAZE FROM SMALLER ISLANDS TODAY.
LATEST FORECAST TRAJECTORIES KEEPS THE VOLCANIC EMISSIONS PLUME
FROM KILAUEA AWAY FROM THE ISLANDS...EXCEPT FOR THE NORMAL AREAS ON
THE KONA AND KAU DISTRICTS OF THE BIG ISLANDS.  LIGHT WINDS ARE
EXPECTED TO CONTINUE TODAY...SO ANY HAZE THAT IS SEEN WOULD BE AND
NOT IMPACT VISIBILITIES AS MUCH AS VOG.

A 1027 MB HIGH IS CENTERED FAR NORTHEAST OF THE STATE WITH A WEAK
RIDGE AXIS EXTENDING FROM THIS HIGH TO JUST NORTH OF KAUAI.
MEANWHILE AN UPPER LEVEL TROUGH IS CENTERED JUST NORTHEAST OF THE
BIG ISLAND.  COLD AIR ASSOCIATED WITH THIS UPPER LEVEL TROUGH IS
KEEPING THE AIRMASS UNSTABLE STATEWIDE AND WILL ALLOW THE HUMID AIR
IN PLACE TO DEVELOP INTO AFTERNOON SHOWER-LADEN CLOUD BUILDUPS.
THERE REMAINS A SLIGHT CHANCE OF THUNDERSTORMS THROUGH THE EVENING
HOURS. LIGHT WINDS WILL ALLOW SEA BREEZES TO DEVELOP AND THESE WILL
PROVIDE THE LOW LEVEL CONVERGENCE NEEDED TO PRODUCE THESE CLOUDS
AND SHOWERS. AS THE SUNSET SETS THIS EVENING...LAND BREEZES WILL
DEVELOP AND CLOUDS AND CHANCES OF SHOWERS DECREASING.

THE OVERALL PATTERN WILL CHANGE LITTLE OVER THE REST OF THE WEEK.
THE UPPER TROUGH WILL WEAKEN...WITH WARMING ALOFT HELPING TO
STABILIZE THE AIRMASS SOME...BUT THERE WILL STILL BE ENOUGH
MOISTURE AND LOW LEVEL INSTABILITY FOR THE AFTERNOON AND EVENING
SHOWERS TO CONTINUE IN AREAS WHERE SEA BREEZES DEVELOP.
TEMPERATURES WILL REMAIN ON THE WARM SIDE IN THE AFTERNOONS...WITH
COOL EVENINGS DUE TO THE LIGHT WINDS.

FOR THE WEEKEND AND EARLY NEXT WEEK...THE MODELS SHOW THE RIDGE
MOVING DIRECTLY OVER THE MAIN HAWAIIAN ISLANDS AS A COLD FRONT
STALLS FAR TO THE NORTH. THIS WILL MAINTAIN WARM AND A BIT MUGGY
CONDITIONS...WITH LIGHT WINDS AND DIURNAL SHOWER CHANCES MAXIMIZING
EACH AFTERNOON AND EVENING.

&&

.AVIATION...
THE AIRMASS OVER THE ISLANDS CONTINUES TO REMAIN MOIST AND UNSTABLE
AS AN UPPER LEVEL TROUGH SIT OVER THE STATE. SEA BREEZES WILL FORM
UNDER LIGHT ESE FLOW AND THE THREAT FOR THUNDERSTORMS TO DEVELOP
STILL REMAINS...ESPECIALLY OVER THE INTERIOR LAND AREAS THIS
AFTERNOON. EXPECT THUNDERSTORMS TO CARRY MVFR TO IFR CONDITIONS AND
HAVE CB TOPS REACHING ABOVE FL350. THERE ARE NO AIRMETS IN EFFECT AT
THIS TIME.

&&

.MARINE...
A SMALL NORTHWEST SWELL IS EXPECTED TO ARRIVE TODAY...AND PEAKING
WEDNESDAY. THIS SWELL WILL BE REINFORCED BY A SMALL NORTHWEST
FRIDAY. THE SOUTH FACING SHORES WILL ENCOUNTER A SERIES OF SMALL
SWELLS FROM THE SOUTH THROUGH THURSDAY...THE LARGEST ARRIVING ON
TUESDAY THROUGH THURSDAY.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

BRENCHLEY/EATON








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